Number of episodes of symptomatic or non-symptomatic hypoglycaemia detected by CGMS throughout the duration of physical activity and subsequent hours until the next morning (threshold: 3 mmol/l or 0.54 g/l).

Duration of hypoglycaemia (min), total time in hypoglycaemia (min, %), time to onset of hypoglycaemia after the start of physical activity, degree (blood glucose level) and severity of hypoglycaemia, area under the algebraic curve during physical activity and in the following hours, nadir of the intervening glucose curve.

To show that in subjects with type 1 diabetes with a subcutaneous continuous insulin infusion, adjustment of the recommended basal insulin flow rate in the event of physical activity allows the subjects to practice sports without any increase in incidence of hypoglycaemia during physical activity or the ensuing hours.

(NB: hypoglycaemia is defined as blood glucose less than 3 mmol/l or 0,54 g/l in accordance with the EMEA definition).

The proposed algorithms consist of a temporary reduction in basal flow of 50 percent or 80 percent (temporary basal flow TBR50 or TBR80) depending on the intensity of physical activity (50 percent of VO2max or 75 percent of VO2max). Switching off the pump will also be studied as an option to adjust insulin dosage in the event of unprogrammed physical activity (temporary reduction of basal flow by 100 percent).

Secondary aims:

Characterisation of hypoglycaemia during and after physical activity based on CGMS data: symptomatic or non-symptomatic nature of hypoglycaemia, time to onset of hypoglycaemia in relation to the start of physical activity, degree and severity of hypoglycaemia.

Evaluation of overall variations in blood glucose in the event of physical activity using CGMS data (area under the curve).

Evaluation of glucose restoration methods used in the event of hypoglycaemia.

Analysis of subgroups of patients with and without hypoglycaemia.

Detailed Description

Inclusion criteria:

Patients aged over 18 years, presenting type 1 diabetes for at least 1 year

Patients consenting to take part in the study and having signed a written informed consent form.

Non-inclusion criteria:

Patients with a history of severe hypoglycaemia in the 6 months prior to entry into the study

Patients unable to detect their hypoglycaemia

Patients with perforating foot ulcer or a known history of heart disease or obliterative arteriopathy of the lower limbs, or a history of cerebrovascular accident, or ongoing proliferative retinopathy or renal failure.

Number of episodes of symptomatic or non-symptomatic hypoglycaemia detected by CGMS throughout the duration of physical activity and subsequent hours until the next morning (threshold: 3 mmol/l or 0,54 g/l).

Secondary criteria:

Duration of hypoglycaemia (min), total time in hypoglycaemia (min, percent), time to onset of hypoglycaemia after the start of physical activity, degree (blood glucose level) and severity of hypoglycaemia, area under the algebraic curve during physical activity and in the following hours, nadir of the intervening glucose curve.

Before starting this study, patients will undergo effort testing and measurement of their VO2max in order to precisely define the different thresholds of physical activity.

Tests and proposed insulin adjustment:

- Tests: Basal period

Each patient will undergo 5 consecutive tests over a 6-month period. The tests will be performed 3 hours after the start of the midday meal in order to define a period during which blood glucose is solely dependent on basal flow. The 5 tests will comprise 4 physical tests and 1 resting test, to be performed in random order:

The 4 physical tests will comprise 2 different levels of intensity (50 percent VO2max, 75 percent VO2max). At each of these levels, patients will test 2 insulin dose adjustment algorithms concerning only the basal flow rate of the insulin pump:

Each physical test will comprise testing on a bicycle ergometer for 40 minutes with:

a 5-minute period during which the intensity of physical activity will be raised

a 30-minute plateau at the desired intensity and power

a 5-minute recovery period. "Prandial" period In the second phase, two further tests at 50 percent VO2max will be performed 90 minutes after the start of the meal in order to evaluate the effect of reducing the rapid-acting insulin bolus at the onset of hypoglycaemia.

At the same time, during the 2 periods ("basal" and "prandial"), patients will be asked to score the intensity of their physical activity on the Borg RPE rating scale.

- Adjustment of insulin dose:

The bolus for the meal preceding physical activity (lunch) will be given as usual, with no deliberate reduction for the ensuing sport.

"Basal" period

The adjustments in basal flow proposed at the time of physical activity will take into account the intensity of the ensuing physical activity:

reduction of basal flow by 50 percent or by 80 percent in the first case

reduction of basal flow by 80 percent or switching off the pump in the second case.

In the event of reduced basal flow, this will be maintained throughout the duration of physical activity and for the 2 hours following the end of physical activity. If the pump is switched off, it will remain switched off throughout the entire duration of physical activity, but it will not be removed in order to maintain the study blind. It will be switched on again routinely at the end of the physical activity period, at the same flow rate as that set prior to physical activity.

- Continuous Monitoring Glucose System (CMGS)

A CMGS to record intervening blood glucose levels will be fitted before lunch and worn until the next morning. Data recorded by the CMGS will not be visible to patients in order to prevent them from attempting to modify their insulin doses based on these values.

Patients will have dinner at 8 o'clock in the evening in their own home in order to allow superimposition of the blood glucose curves and facilitate their interpretation. The CMGS will be removed the next morning after breakfast.

Adjustment of the Recommended Basal Insulin Flow Rate in the Event of Physical Activity

Adjustment of the Recommended Prandial Insulin in the Event of Physical Activity

Intervention ICMJE

Other: 50%VO2maxTBR50

The basal rate of the pump will be adjusted in accordance with the intensity of physical activity being performed for moderate physical activity (50% VO2max),a temporary basal rate will be reduced by 50%

Other: 50%VO2max TBR80

The basal rate of the pump will be adjusted in accordance with the intensity of physical activity being performed for moderate physical activity (50% VO2max),a temporary basal rate will be reduced by 80%

Other: 75%VO2max TBR80

The basal rate of the pump will be adjusted in accordance with the intensity of physical activity being performed for moderate physical activity (75% VO2max),a temporary basal rate will be reduced by 80%

Other: 75%VO2max TBR100

Turning off the pump (75%VO2max TBR100).However, in order to maintain the study blindfold, the pump will be switched off but not removed

Other: Rest

Patient will be in rest, basal insulin flow rate will not be change

Study Arm (s)

50% VO2 max, BFR reduced by 50%

The basal rate of the pump will be adjusted in accordance with the intensity of physical activity being performed for moderate physical activity (50% VO2max),a temporary basal rate will be reduced by 50%

Intervention: Other: 50%VO2maxTBR50

50% VO2 max,BFR reduced by 80%

The basal rate of the pump will be adjusted in accordance with the intensity of physical activity being performed for moderate physical activity (50% VO2max),a temporary basal rate will be reduced by 80%

Intervention: Other: 50%VO2max TBR80

75% VO2 max, BFR reduced by 80%

The basal rate of the pump will be adjusted in accordance with the intensity of physical activity being performed for moderate physical activity (75% VO2max),a temporary basal rate will be reduced by 80%.

Intervention: Other: 75%VO2max TBR80

75% VO2 max, pump switched off

Turning off the pump (75%VO2max TBR100).However, in order to maintain the study blindfold, the pump will be switched off but not removed.

Intervention: Other: 75%VO2max TBR100

Rest

Patient will be in rest, basal insulin flow rate will not be change.

Intervention: Other: Rest

Publications *

Not Provided

* Includes publications given by the data provider as well as publications
identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.

Patients consenting to take part in the study and having signed a written informed consent form.

Exclusion Criteria:

Patients with a history of severe hypoglycaemia in the 6 months prior to entry into the study

Patients unable to detect their hypoglycaemia

Patients with perforating foot ulcer or a known history of heart disease or obliterative arteriopathy of the lower limbs, or a history of cerebrovascular accident, or ongoing proliferative retinopathy or renal failure.